Evaluation Of Surface Topography Research Articles

Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications.

Background:Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique.Materials and Methods:Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3–0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine.Results:The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer.Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength.Conclusions:Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

On the combined use of nanoparticles and a proper solvent/non-solvent system in preparation of superhydrophobic polymer coatings

A novel method including combined use of nanoparticles and non-solvent is proposed for fabrication of superhydrophobic polystyrene coatings. The proposed method results in utterly homogenous and mechanically stable coatings with excellent adhesion to the substrate as compared to the other commonly used solution-based methods. It is proved that individual use of nanoparticles and non-solvent could lead to superhydrophobic behavior but at the price of adding very high contents. Based on water contact angle results, the proposed method causes a significant reduction in the required contents of nanoparticles (150 wt% to 20 wt% with respect to the polymer) and non-solvent (33 vol% to 9–16 vol%) for achieving superhydrophobicity. A thorough investigation of surface composition and morphology is also conducted via X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. Moreover, a different approach is employed for evaluation of surface topography using diverse roughness parameters. It was found that a combination of roughness parameters should be considered for a proper surface analysis instead of only using average roughness and root mean square. It was also demonstrated that the surface roughness uniformity is another key factor to achieve a self-cleaning behavior.

Investigating the effect of WEDM process parameters on 3D micron-scale surface topography related to fractal dimension

The wire electric discharge machining (WEDM) process is a violent thermal process in which a certain volume of metal is eroded by thousands of electrical discharges in a fraction of 1 s. The process is widely used in tooling, especially in the cutlery and mold industry. However, the poor properties of surfaces such as high tensile residual stresses, high surface roughness, white layers, and microcracks are generated in the process. These properties vary with different levels of process parameters. In this paper, a new graphical evaluation of micron-scale surface topography on WEDM process is proposed by the fractal method. The objective is to quantify 3D micron-scale surface topography effect of process parameters such as pulse-on time, pulse-off time, cutting feed rate, wire tension, wire speed, and water pressure on working surface in dressing. Firstly, adaptive measuring was conducted on the basis of 3D micron-scale surface topography by the Ł18(21×35) Taguchi standard orthogonal experiments; secondly, the fractal dimension was conducted to identify 3D micron-scale surface topography; and finally, the effect of WEDM process parameters was investigated with reference to the fractal dimension (FD) of 3D micron-scale surface. The results have shown that the pulse-on time is the most dominant factor in affecting the surface texture. Moreover, the interaction effect between process parameters is analyzed. It has also been observed that the optimized combination of pulse-on time of 3 μs, pulse-off time of 20 μs, cutting feed rate of 4 mm/min, wire tension of 6 kgf, wire speed of 6 m/min, and water pressure of 5 kgf is suitable for 3D micron-scale surface, and the FD of 3D micron-scale surface is increased by 11 %.

Surface Topography of Mini-Size Diamond Wheel in Ultrasonic Assisted Grinding (UAG)

The objectives of this paper are to describe a quantitative evaluation of mini-size diamond grinding wheel surface topography in Ultrasonic Assisted Grinding (UAG) process and demonstrate the effects of topography on grinding characteristics. In this study, threedimensional (3D) analysis of the wheel working surface was observed using a Scanning Electron Microscope (SEM) with four electron probes (hereafter described as 3D-SEM) in an on-surface UAG process. These results indicated that a good wheel surface maintained in the UAG process is related to the number and the area of cutting edges. Additionally, the resulting topographic features of the grinding wheel surface are closely related to low grinding forces and allow easy manufacturing of a mirror workpiece surface.

Evaluation of surface topography and bearing properties of hard turned surfaces using differently shaped PCBN tools

S u m m a r y This paper deals with hard turning using conventional and wiper polycrystalline cubic boron nitride (PCBN) tools. 3D surface topographies and bearing area curves were determined and compared after hard turning with differently shaped cutting tools. Machined parts were made of a 100Cr6 (AISI 5210) hardened bearing steel with Rockwell hardness HRC=60 ± 1 HRC.

Evaluation of tensile strength and surface topography of orthodontic wires after infection control procedures: An in vitro study.

Aim:The aim of this study is to evaluate, the influence of four types of sterilization/disinfection procedures (autoclave, hot air oven, glutaraldehyde, and ultraviolet [UV] light) on the tensile strength and surface topography of three orthodontic wires (stainless steel (SS), titanium - molybdenum alloy [TMA], and cobalt chromium (CoCr)).Materials and Methods:Sample comprised of three types of 8 inches straight length segments of orthodontic wires. They were divided into three groups according to wire composition comprising of 50 samples each. Totally 50 samples of each group were then equally divided into five subgroups according to sterilization method. After sterilization and disinfection of the experimental group, surface topography was examined with scanning electron microscope (SEM) and tensile strength was tested using universal testing machine.Result:The results of this study show that the mean ultimate tensile strength (UTS) of SS wire after four sterilization procedures were similar to the control group (1845.815 ± 142.29 MPa). The mean UTS of TMA wire increases after four sterilization procedures when compared with the control group (874.107 ± 275.939 MPa). The mean UTS of CoCr wire remains same after UV light disinfection, but increases after other three sterilization procedures when compared with the control group (1449.759 ± 156.586 MPa). SEM photographs of the present study shows gross increase in pitting roughness of the surface topography of all the three types of wires after four types of sterilization.Conclusion:Orthodontists who want to offer maximum safety for their patients can sterilize orthodontic wires before placement, as it does not deteriorate the tensile strength and surface roughness of the alloys.

142 低サイクル疲労過程におけるSUS316NGの表面性状評価(材料力学・機械材料)

142 低サイクル疲労過程におけるSUS316NGの表面性状評価(材料力学・機械材料)

Evaluation of surface topography of zirconia after Er:YAG laser etching

Evaluation of surface topography of zirconia after Er:YAG laser etching

Based on L∞ Regression with Robust Fitting Algorithm for Surface Topography Evaluation of the Inner Wall of the Cylinder Jackets

For lubrication, energy saving and emission reduction, some "valley" textures are required for the finishing cylinder liner inner surface to store oil, but some difficulties are brought by this hierarchical functional surface during the surface quality assessment.The reference which is extracted by traditional filtering method and the baseline fitting method often be lowered by the " valley " and eventually deviate from the ideal surface, resulting in the distortion of the reference plane, making the subsequent parameters can not be assessed precisely. Nowadays, to solve this problem, robust Gaussian regression filtering is highly recognized, but eventually being too time-consuming and can not be promoted. Therefore, a new robust regression fitting algorithm is proposed, which is based on quadratic function and trigonometric function, combined with the Levenberg- Marquardt algorithm's minimizes the maximum deviation(least absolute value, L∞) regression method, making lower the impact of outlier on the hierarchical functional surface,then, reconstruct the datum quickly and perfectly to be achieved. The simulation results show that compared with least squares(Ls), robustness is greatly improved by the proposed method; compared with Gaussian regression filter, it has the same robustness, but the speed increases nearly 105 times, and the deviation between the surface in three-dimensional amplitude parameters and function parameters with the true value do not exceed 2% in the ISO 25178-2 standard. Finally, the experiments are conducted on the actual cylinder liner inner wall surface, and the results show that the new method is more robust comparing with Ls, more time-saving comparing with Gaussian regression filter, and it has high precision and high efficiency during extracting datum.

Research on the Surface Roughness Parameters of Micro-EDM

The surface topography errors of micro-EDM are mainly composed of surface roughness, surface waveness and so on. Research shows that the surface morphology provides a lot of useful information, which has serious influence on the friction and lubrication characteristics of the surface. However, for the micro-EDM surface topography evaluation problem, researchers have been using surface roughness parameters and evaluation method of mechanical process, which restrict the micro-EDM technology further development. On this account, the surface roughness parameters of micro-EDM have been deeply studied in this paper according to its technology characteristics and the surface morphology characteristics, therefore, the main researches and creative points are obtained, which the influence that the surface roughness of micro-EDM parts impact on their using performance is analyzed, and based on the surface morphology characteristics, some roughness evaluation parameters are given respectively according to peaks and valley, moreover, their numerical calculation are also gained.

Methodology for the evaluation of 3D surface topography in multiple indentation processes

Elementary indentation processes are relatively simple compression processes and they are quite extended in many fields of the industry. Nevertheless, the concatenation of these processes is a new approach and has interest from a technological point of view. Incremental forming processes can be carried out in CNC machines with more flexibility, lower force requirements and simpler tools than in conventional forging processes. The purpose of this work is the analysis of the three-dimensional geometry resulting from the multiple indentation process. Based on the surface rugosity parameters defined in the specification standard ISO 4287, the state of the 3D-formed surface by several types of tools is studied and a predictive evaluation model has been developed in order to quantify, by means of shape parameters Sa and SM, the topography of the expected surface and the amount of material displaced depending on the technological and geometrical characteristics of the process.

Atomic force microscopy and scanning electron microscopy evaluation of efficacy of scaling and root planing using magnification: A randomized controlled clinical study

Aim:A randomized controlled clinical study was undertaken to evaluate the effectiveness of scaling and root planing (SRP) by using Magnifying Loupes (ML) and dental operating microscope (DOM).Materials and Methods:A total of 90 human teeth scheduled for extraction from 18 patients aged between 25 and 65 years suffering from generalized chronic severe periodontitis were randomly assigned to three treatment groups. Group 1 consisted SRP performed without using magnification (unaided), Group 2-SRP with ML and Group 3-SRP with DOM. Following extractions, samples were prepared for (i) evaluation of surface topography by atomic force microscopy, (ii) presence of smear layer, debris by scanning electron microscopy (iii) elemental analysis by energy dispersive X-ray analysis. Data was subjected to statistical analysis using analysis of variance, post-hoc (Tukey-HSD) and Chi-square test.Results:Statistically significant (P < 0.001) difference was found among the different treatment groups. Group 3 was the best while Group 1 was the least effective technique for SRP. Order of efficacy in terms of the surface was found to be - Palatal < Lingual < Distal ≃ Mesial < Buccal. Efficiency in mandibular to maxillary teeth was found to be significant (P < 0.05), also anterior to posterior teeth (P < 0.05).Conclusion:Magnification tools significantly enhance the efficacy of supragingival and subgingival SRP.

Surface Topography Characterization in Steel Running-in Process of Dry Sliding Friction

Running-in is an important and inevitable wear process for machine system, and it plays an indispensable role in extending service life and improving operating performance. Surface topography appears as a significant feature of friction pairs. Therefore, study on modification of surface topography in running-in is crucial to control surface quality and then achieve improvement of machine system. In this paper, to understand the evolution of surface topography in running-in process, steel dry sliding running-in experiments were conducted, and surface topographies in running-in were evaluated with the areal surface evaluation parameters. The results reveal that surface topography evaluation could provide valuable information about wear status of steel running-in process of dry sliding friction, amplitude parameters, area and volume parameters, and hybrid parameters play different and important roles in characterization of surface topography modification in running-in.

Evaluation of Effect of Oral Microorganism on Surface Topography of Arylic Resin Denture Base Materialby Three Dimensional Profilometry Using Laser Triangulation Sensor- In Vitro Study

Purpose: The aim of this study was to evaluate the effect of oral microorganism on surface topography of acrylic resin denture base material. Materials and methods: Fifty rectangular plates of dimensions 30mm x 20mm x 1 mm were fabricated with heat polymerizing acrylic resin denture base material. an area of 10mm x 10 mm in the center of each acrylic plate was marked for evaluation of surface topography by Laser Triangulation Sensor.The plates were then sterilized by immersion in 2 % Gluteraldehyde for 30 minutes, and placed in sterilized containers. saliva sample were collected from 40 healthy edentulous people of 40 to 60 years in age wearing acrylic complete denture. 0.1 ml of saliva was immediately poured on central portion of each were placed in incubator at 37 degree centigrade for 72 hr. after 72 hr each plate was inspected for bacterial colonies. Results: The mean value of difference of mean surface roughness value (ra) of acrylic plates before culture and after culture of microorganism is 2.13343 with overall standard deviation of 0.9964, and standard error 0.1821. Conclusion: The acrylic resin plates showed some amount of roughness even after polishing (mean surface roughness value ‘Ra’) before culture of microorganism on them. The acrylic resin plate showed an increase in mean surface roughness after culture of microorganism. Thus this roughness will deteriorate the denture by the time, even after the use of latest denture cleanser and other auxiliaries, by offering more plaque and microorganism accumulation and cycle go on.

Features of neurohumoral regulation in flat back posture and initial stage scoliosis

The appearance and progression of idiopathic scoliosis (IS) are considered to be the result of an inequality of the spinal column and spinal cord longitudinal growths. Consequently, normal afferent input from spinal cord elements to the highest parts of the central nervous system (CNS) is altered even by a minor hyperextension of spinal cord structures. De-afferentiation leads to forming a hyperactive deterministic structure and inadequacy of neurohumoral processes of regulation in thalamus–hypothalamus–hypophysis. The resulting neurohumoral abnormalities could be defined in experimental models via patients' blood serum testings. The aim of this study was to define prognostically valuable biotest indexes in the early stages of scoliotic deformity progression. Results of blood serum testing of 15 children with flat back posture and 15 children with first and second grade IS, subjects 9–12 year old, are presented in this paper. Biotest results of 12 healthy children of the same age served as the control. Method of biotesting: rats spinalized at the thoracic level (Wistar male rats weighing 200 g) were injected with 0.1 mL of blood serum of investigated children at the L3–L5 levels. Features of the rearrangement at the spinal cord level were judged by changes in the spontaneous and evoked electromyographic (EMG) activity of the hind extremities. The EMG rate is the quantity of EMG discharges in a time unit. Initial EMG activity of a rat before blood serum administration is considered to be 100%. The total coefficient of disorders was calculated according to 24 factors of antagonistic muscles EMG reactions. All patients were examined employing the following methods: computer evaluation of surface topography, surface EMG of paravertebral muscles, four-field weighting, and blood samples for biotesting. The most informative biotest indexes pointing to IS progression in children were chosen. Reliable differences in the groups with respect to the model were identified by tonic reaction changes and irradiation of excitation to muscles of an opposite extremity after electrical stimulation ( p ≤0.05). Reflex responses in IS were changed on one of the sides (right in right-sided and left in left-sided scoliosis), but in postural fault EMG activity increased in extensors on both sides. Biotesting findings allow for the progression of scoliotic deformity to be prognosticated. This is important for the selection of the proper treatment strategy.

A comparison of authomatic vs. manual detection of anatomical landmarks during surface topography evaluation using the formtric 4D system

Background The Formetric 4D System (Diers International GmbH, Schlangenbad Germany) is a popular system for measuring surface topography in patients with adolescent scoliosis [1-4]. The system automatically detects anatomic landmarks on the patient, but then gives the user the opportunity to make adjustments to those landmarks if necessary. The purpose of this study was to see whether there would be more variability in repeated measurements if the landmarks were adjusted by the clinician or if they were left in the place where the machine had put them.

The effect of sand-blasting and hydrofluoric acid etching on Ti CP2 and Ti CP4 surface topography

Titanium is widely used in biomedical applications from many years for its interesting properties, nevertheless there are a large number of researchers studying the way to improve the performances of biomedical devices. A large number of papers concern the study of “commercially pure titanium” (Ti CP) but, very often, no details are indicated regarding: 1) the type of Ti CP used; 2) the sandblasting process; and 3) the analytic evaluation of surface topography. In this paper, the effect of sandblasting duration (1, 2, 4, 8 min) and hydrofluoric acid (HF) etching, as well as their combined or synergic effect, on the surface topography of CP grade 2 and grade 4, have been investigated. Results obtained show that sandblasting treatment duration should be different for Ti CP grade 2 and Ti CP grade 4 to achieve similar topography. The shape of the surface is highly modified after acid etching. The latter produces “peaks” when applied to not sand- blasted coupons, whilst cuts the “top of the peaks” in the sandblasted samples. Further we confirm that, the roughness parameter Ra (or Sa), is not sufficient to describe “the surface status” and we propose to use additional para- meters like: Sq, Sku and Ssk, to unequivocally describe surface topography of implants as well as well defined test procedures.

Effect of 15% carbamide peroxide bleaching gel on color stability of giomer and microfilled composite resin: An in vitro comparison

Objectives: The effect of 15% carbamide peroxide bleaching gel on color stability and surface topography of a giomer and a microfilled composite resin was evaluated in the present in vitro study. Study design: Forty discs measuring 10 mm in diameter and 1 mm in thickness were prepared from a giomer and a microfilled composite resin. Each material yielded 20 discs with completely smooth surfaces. Then a spectrophotometer was used to measure L* (lightness), a* (redness, greenness) and b* (blueness, yellowness) color coordinates of all the discs. Subsequently, the specimens were subjected to 15% carbamide peroxide bleaching gel. After measuring the color coordinates once again, color changes (ΔE*) were calculated by the CIELAB system. Six specimens from each material (three specimens before bleaching agent application and three specimens thereafter) were viewed under an atomic force microscope (AFM) for surface topography evaluation. Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests at α=0.05. Results: There were no statistically significant differences in color changes (ΔE*) between the two materials (P>0.05). In addition, no significant differences were detected in surface roughness between composite resin and giomer discs before and after bleaching (P>0.05 for both). However, in both materials the differences in surface roughness were significant before and after bleaching procedures (P<0.001). Conclusions: Based on the results of the present study it was concluded that 15% carbamide peroxide does not induce clinically detectable color changes in composite resin and giomer despite an increase in surface roughness. Key words:Bleaching, color stability, giomer, microfilled composite.

Damage Assessment Using Fractography as Failure Surface Evaluation: Applications in Industrial Metalworking Machinery

Fractography is a powerful analytic tool for the evaluation of failure surface topography and root-cause analyses. Fractography, embracing both light and electron optics methods, is utilized in modern failure analysis and is recognized by the engineering community as a unique process for industrial problem solving, evaluating machinery/component failures, and providing solutions for performance improvements. In the present study, the role of fractography is highlighted through characteristic failures of industrial machinery components. Low-power stereomicroscopy and Scanning Electron Microscopy (SEM) micro-fractography are the principal analytic tools that were used in the context of the present research.

Study on Grinding Machinability of Titanium Alloy Using SiC Abrasive

Experimental results of Ti-6-2-4-2S, Ti-6-4 and Ti-5-5-5-1-1 are detailed in this paper with conventional surface grinding using SiC abrasive under dry conditions. Measurements of grinding forces, surface topography and metallurgical structure of ground surface were taken to investigate the grinding mechanism of these materials. The results showed grinding force ratios to these materials were between 1.35 to 2.25 at all material remove rates, but the specific energy to Ti-5-5-5-1-1 and Ti-6-2-4-2S were little higher than Ti-6-4. Evaluation of ground surface topography indicated they were visually free of crack and burn. At the same grinding parameters, Ti-5-5-5-1-1 had the maximum depth of heat-affected zone because of its poor high temperature properties.